In a large pot, bring potatoes to a boil in salted water. Reduce heat to a rapid simmer. Add leek and kale and cook until potatoes are tender about 10 minutes. Drain and transfer to a large bowl.

In a large cast-iron skillet, cook bacon over medium-high until crisp, 8 to 10 minutes. With a slotted spoon, transfer to bowl with vegetables. Add salt and pepper. Mash potato mixture until a few lumps remain. Form into 12 patties.

Add butter to pan and melt over medium heat. In batches, cook cakes until golden on both sides, about 6 minutes, flipping once.

A nutritional powerhouse, kale is a great source of vitamins A and C, calcium, and cancer-fighting phytonutrients. It has a mild cabbagey taste but none of the bitterness of other winter greens.

You can substitute other hearty greens such as collards or dino kale. If using chard or spinach, reduce cooking time and add at the end of cooking.